1. Field of the Invention
The invention relates to a winding contact having a winding post which is attached in a contact casing made of spring plate and carrying a contact element for the centered and torsional holding of the winding contact in a cylindrical contact hole of a contact housing made of electrically insulating plastic.
2. The Prior Art
In the case of electric plug connections with winding contacts in the case of which the wire connection is executed as a nonsoldered connection in the so-called winding or wire wrap technique, it is necessary to absorb with the contact the torque occurring in the case of winding on the winding or wire wrap post, which contact must therefore not rotate in the contact hole of the contact housing. Winding contacts therefore must be equipped with rotary safeties.
A constructionally simple rotary safety will be obtained whenever the contact hole is made non-round in an axial area and whenever the contact is correspondingly constructed. Such a plug connection is described, for example, in the German No. OS 26 16 621. Such a rotary safety necessitates that, for every contact housing, matching contacts be provided, and this contradicts the universality of the contact housing striven for for economic reasons because the usually round contacts cannot be then used.
For the rotary safety of contacts additional parts are frequently used in the most varied embodiments, such as described, for example, in the German patent No. 23 50 775, the U.S. Pat. No. 4,090,771 and in the French Pat. No. 2,263,615. The separate anchoring part will be attached frequently to the contact or it is placed over the winding post and may consist of a lamella or a peg. Bipartite rotary-secured contacts are expensive in their production and uneconomical, and moreover their handling is cumbersome, whereby considerable wear and tear often occurs on the contact housing since, during the replacement of the contacts, the walls for the contact hole may easily be greatly damaged, or as especially in the case of multiple contacts with a multiplicity of contacts arranged closely beside one another, they could even be destroyed.
In the market place, one-part rotary-secured contacts are available in which the essentially casing-shaped resilient rotary safety is made of the same piece of material as the contact body. Known embodiments of such single rotary-secured contacts however turn out to be unsatisfactory insofar as above all, because of a resilient springiness of the springy rotary safety and of the circumstance that stronger torques and radial forces acting upon the contact inserted into a contact hole, lead to changes of diameter in the case of the rotary safety and/or to a reduction of the penetrating depth of the clamping elements in the wall of the contact hole, only relatively weak torques must be applied for the production of a winding contact, in order to exclude with assurance a loosening of the rotary safety in the case of winding, and thus one must count with a more frequent occurrence of defective electrical connections subject to breakdowns between the conducting wire and the contact piece.
Therefore, it was the task of the invention to create a rotatably secured winding contact of the initially mentioned type in the case of which and on the assumption that, whenever it is inserted into a contact hole with a circular cross section, it will permit the essentially desirable mobility of the contact piece in the contact hole for plug connections and at the same time center the plug connection area as well as the winding post well, that the rotary safety is unchangeably reliable even after frequent contact loads, as they occur especially in the case of plugging connections themselves or in the case of a pull on the connected conducting wire, and in the case of which torques and radially acting forces will not change the penetrating depth of anchoring elements in the wall of the contact hole disadvantageously. Furthermore, the exchangeability is to be ensured for the winding contact, that is to say, the winding contact should be such that upon taking the contact housing from the contact hole, the wall of the contact hole will not be destroyed or damaged so badly that it no longer satisfies the electric requirements, especially with regard to the insulation thickness, and finally, the winding contact is to be producible also in an economic mass production.